The present invention relates to a device for applying light to an inner surface of a cylinder and to a beam transformation device that is particularly suitable for such a device.
Definitions: The terms light or illumination or laser radiation are not intended to be limited to the visible spectral range of the light. Rather, the terms light or illumination or laser radiation in the context of this application are used for electromagnetic radiation over the entire wavelength range from FIR to the XUV. Propagation direction of the laser beam or the light refers to an average propagation direction of the laser radiation or light, in particular when this is not a plane wave or is at least partially divergent. Laser beam, light beam, sub-beam or beam may refer not only to an idealized beam of geometrical optics, but also to a real light beam, such as a laser beam having a Gaussian profile or a modified Gaussian profile, such as a super-Gaussian profile or a top hat profile, which does not have an infinitesimally small beam cross-section, but rather an extended beam cross-section.